Lathe-dog



- .wi'L. MASON.

LAT HE DOG APPLICATION FILED APR.10,19I9.

-1 8 ,822. Patented June 7, 1921.

stares earner cries.

LATHE-DOG.

aeoeaa Specification of Letters Patent.

Patented June '7, 1921.

Application filed April 10, 1919. Serial No. 288,913.

To all whom it may concern:

Be it known that 1, WIL IAM L. MASON, a citizen of the United States,residing at Holyoke, in the county of Hampden and State ofMassachusetts, have invented certain new and useful Improvements inLathe- Dogs, of which the following is'a specifi cation. i r

This invention relates to lathe-dogs and the primary object is toimprove the general construction of devices of this character so that aneffective grip may be obtained while the device is in use withoutresorting to springs, adjusting screws, clamp elements or similardevices which rapidly wear and become defective.

The invention further aims to provide a lathe-dog which will be simplein construction and consists of only two movable parts arranged tocooperate for effecting a firm grip on the work. so that the pullexerted by the lathe mechanism will not only revolve the work but willalso cause the same to be tightly held in position until such time asthe lathe is stopped.

Another object of the invention is to provide a lathe-dog of thischaracter which will bepractically automatic in its releasing actionwhen the lathe is stopped.

The invention further aims to provide a device of this character whichcan be quickly mounted in position and applied thereby savingconsiderable time and thus improving the general efiiciency and speed ofthe workman using the device.

A further object of this invention is the production of a device of thischaracter which consists of comparatively few parts and is simple inconstruction but durable and well adapted to withstand the rough usageto which devices of this character are ordinarily subjected.

For a full description of the invention and the advantages and meritsthereof, reference is to be had to the following description andaccompanying drawings, in which Figure 1 is a side elevation of the dogconstructed in accordance with my invention.

Fig 2 is a longitudinal section through the same.

Fig. 3 is an edge elevation.

Referring to the drawings, wherein is illustrated the preferred form ofmy invention, wherein like numerals of reference indicate like orcorresponding parts throughout the several views, the head has one endsubstantially circular and provided with a clrcular opening 2 throughwhich the work may be passed as indicated by broken lines in Fig. 1. Theopposite end of the head 1 is extended and this extended portion isbifurcated byproviding the slot 3 which extends from the end of the headinwardly to intersect the opening 2 thereby providing the laterallyspaced ears 4. A gripping member 5 is provided for cooperation with thehead 1 and consists of the shank 6 having an eccentric disk or plate 7formed at one end. This eccentric disk 7 has a curved marginal edge 8provided throughout a portion of its, length with the grippingteeth 9.The opposite end of the shank 6 carries a right angularly projectingfinger 10, this finger being similar to the finger usually employed onlathe-dogs for engaging the driving plates to receive the force exertedfor turning the work. The arrow in Fig. 2 indicates the direction ofpull exerted by the lathe when the device is in use.

The disk 7 is disposed between the ears 4 and is pivotally mounted onthe pivot pin 11 which has its ends fixed in the ears 4. This pivot pinis set at one side of the longitudinal center line of the head 1, sothat it is disposed at one side of the center of the ear 4. The disk 7is eccentrically mounted as shown onthepin 11, the'opening 12 for thepin being disposed at one side of the center of point from which thecurved edge 8 is struck.

It will be obvious that when a pull is exerted on the finger 10 to movethe same in the direction indicated by the arrow in Fig. 2 the eccentricplate 7 will swing on the pivot pin 11' and the teeth 9 will be swunginto the space formed by the opening 2 so that a firm grip is obtainedon the work received in the opening. The head being bifurcated toprovide the ears 4 between which the eccentric disk is mounted, preventslateral loosening or play of the disk and consequently desired rigidityis obtained and the parts are firmly held in applied position withoutthe use of springs or set screws. As soon as pressure or pull on thefinger 10 ceases, the shank 6 may be easily swung so that the teeth maybe readily disengaged from the work and, in fact, the teeth will loosentheir grip immediately upon stopping of the lathe. The loosening of thelocking member, therefore, is substantially automatic and the grippingaction of the locking member is automatic in so far as it engages thework with greater pressure and the speed of the lathe increases.

The foregoing description and accompanying drawing have reference towhat "might be considered to be the approved or preferred form of myinvention. I desire it to be understood that I may make such changes inthe construction, combination and arrangement of parts, materials,dimensions, et cetera, as may prove expedient and fall within the scopeof the appended claim. 7

7 Having thus fully described my invention what I claim as new anddesire to secure by Letters Patent, is

In a lathe-dog, an annular head provided with a slotted elongated side,a lever pivotally mounted Within said slot and provided with anangularly projecting finger, said lever provided with a circular facestruck from the middle of said lever, the pivotal mount for said leverbeing positioned to the side of said middle on said lever and distantfrom the inner part of said annulus, so that when said middle is radialto the center of said annulus said annulus will receive a member to beclamped of almost the size of its inner diameter. c In testimony whereofI aflix my signature in presence of two witnesses.

. WILLIAM L. MASON.

Witnesses: 1

CEoELIA A. FREEMAN, RUSSELL L. DAVENPORT.

